--- /dev/null
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * MikroTik RB91x NAND flash driver
+ *
+ * Main part is copied from original driver written by Gabor Juhos.
+ *
+ * Copyright (C) 2013-2014 Gabor Juhos <juhosg@openwrt.org>
+ */
+
+/*
+ * WARNING: to speed up NAND reading/writing we are working with SoC GPIO
+ * controller registers directly -- not through standard GPIO API.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mtd/rawnand.h>
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/partitions.h>
+#include <linux/platform_device.h>
+#include <linux/gpio/consumer.h>
+#include <linux/version.h>
+#include <linux/of_platform.h>
+
+#include <asm/mach-ath79/ar71xx_regs.h>
+
+/* Bit masks for NAND data lines in ath79 gpio 32-bit register */
+#define RB91X_NAND_NRW_BIT BIT(12)
+#define RB91X_NAND_DATA_BITS (BIT(0) | BIT(1) | BIT(2) | BIT(3) | BIT(4) \
+ | BIT(13) | BIT(14) | BIT(15))
+#define RB91X_NAND_LOW_DATA_MASK 0x1f
+#define RB91X_NAND_HIGH_DATA_MASK 0xe0
+#define RB91X_NAND_HIGH_DATA_SHIFT 8
+
+enum rb91x_nand_gpios {
+ RB91X_NAND_READ,/* Read */
+ RB91X_NAND_RDY, /* NAND Ready */
+ RB91X_NAND_NCE, /* Chip Enable. Active low */
+ RB91X_NAND_CLE, /* Command Latch Enable */
+ RB91X_NAND_ALE, /* Address Latch Enable */
+ RB91X_NAND_NRW, /* Read/Write. Active low */
+ RB91X_NAND_NLE, /* Latch Enable. Active low */
+
+ RB91X_NAND_GPIOS,
+};
+
+struct rb91x_nand_drvdata {
+ struct nand_chip chip;
+ struct device *dev;
+ struct gpio_desc **gpio;
+ void __iomem *ath79_gpio_base;
+};
+
+static inline void rb91x_nand_latch_lock(struct rb91x_nand_drvdata *drvdata,
+ int lock)
+{
+ gpiod_set_value_cansleep(drvdata->gpio[RB91X_NAND_NLE], lock);
+}
+
+static int rb91x_ooblayout_ecc(struct mtd_info *mtd, int section,
+ struct mtd_oob_region *oobregion)
+{
+ switch (section) {
+ case 0:
+ oobregion->offset = 8;
+ oobregion->length = 3;
+ return 0;
+ case 1:
+ oobregion->offset = 13;
+ oobregion->length = 3;
+ return 0;
+ default:
+ return -ERANGE;
+ }
+}
+
+static int rb91x_ooblayout_free(struct mtd_info *mtd, int section,
+ struct mtd_oob_region *oobregion)
+{
+ switch (section) {
+ case 0:
+ oobregion->offset = 0;
+ oobregion->length = 4;
+ return 0;
+ case 1:
+ oobregion->offset = 4;
+ oobregion->length = 1;
+ return 0;
+ case 2:
+ oobregion->offset = 6;
+ oobregion->length = 2;
+ return 0;
+ case 3:
+ oobregion->offset = 11;
+ oobregion->length = 2;
+ return 0;
+ default:
+ return -ERANGE;
+ }
+}
+
+static const struct mtd_ooblayout_ops rb91x_nand_ecclayout_ops = {
+ .ecc = rb91x_ooblayout_ecc,
+ .free = rb91x_ooblayout_free,
+};
+
+static void rb91x_nand_write(struct rb91x_nand_drvdata *drvdata,
+ const u8 *buf,
+ unsigned len)
+{
+ void __iomem *base = drvdata->ath79_gpio_base;
+ u32 oe_reg;
+ u32 out_reg;
+ u32 out;
+ unsigned i;
+
+ rb91x_nand_latch_lock(drvdata, 1);
+
+ oe_reg = __raw_readl(base + AR71XX_GPIO_REG_OE);
+ out_reg = __raw_readl(base + AR71XX_GPIO_REG_OUT);
+
+ /* Set data lines to output mode */
+ __raw_writel(oe_reg & ~(RB91X_NAND_DATA_BITS | RB91X_NAND_NRW_BIT),
+ base + AR71XX_GPIO_REG_OE);
+
+ out = out_reg & ~(RB91X_NAND_DATA_BITS | RB91X_NAND_NRW_BIT);
+ for (i = 0; i != len; i++) {
+ u32 data;
+
+ data = (buf[i] & RB91X_NAND_HIGH_DATA_MASK) <<
+ RB91X_NAND_HIGH_DATA_SHIFT;
+ data |= buf[i] & RB91X_NAND_LOW_DATA_MASK;
+ data |= out;
+ __raw_writel(data, base + AR71XX_GPIO_REG_OUT);
+
+ /* Deactivate WE line */
+ data |= RB91X_NAND_NRW_BIT;
+ __raw_writel(data, base + AR71XX_GPIO_REG_OUT);
+ /* Flush write */
+ __raw_readl(base + AR71XX_GPIO_REG_OUT);
+ }
+
+ /* Restore registers */
+ __raw_writel(out_reg, base + AR71XX_GPIO_REG_OUT);
+ __raw_writel(oe_reg, base + AR71XX_GPIO_REG_OE);
+ /* Flush write */
+ __raw_readl(base + AR71XX_GPIO_REG_OUT);
+
+ rb91x_nand_latch_lock(drvdata, 0);
+}
+
+static void rb91x_nand_read(struct rb91x_nand_drvdata *drvdata,
+ u8 *read_buf,
+ unsigned len)
+{
+ void __iomem *base = drvdata->ath79_gpio_base;
+ u32 oe_reg;
+ u32 out_reg;
+ unsigned i;
+
+ /* Enable read mode */
+ gpiod_set_value_cansleep(drvdata->gpio[RB91X_NAND_READ], 1);
+
+ rb91x_nand_latch_lock(drvdata, 1);
+
+ /* Save registers */
+ oe_reg = __raw_readl(base + AR71XX_GPIO_REG_OE);
+ out_reg = __raw_readl(base + AR71XX_GPIO_REG_OUT);
+
+ /* Set data lines to input mode */
+ __raw_writel(oe_reg | RB91X_NAND_DATA_BITS,
+ base + AR71XX_GPIO_REG_OE);
+
+ for (i = 0; i < len; i++) {
+ u32 in;
+ u8 data;
+
+ /* Activate RE line */
+ __raw_writel(RB91X_NAND_NRW_BIT, base + AR71XX_GPIO_REG_CLEAR);
+ /* Flush write */
+ __raw_readl(base + AR71XX_GPIO_REG_CLEAR);
+
+ /* Read input lines */
+ in = __raw_readl(base + AR71XX_GPIO_REG_IN);
+
+ /* Deactivate RE line */
+ __raw_writel(RB91X_NAND_NRW_BIT, base + AR71XX_GPIO_REG_SET);
+
+ data = (in & RB91X_NAND_LOW_DATA_MASK);
+ data |= (in >> RB91X_NAND_HIGH_DATA_SHIFT) &
+ RB91X_NAND_HIGH_DATA_MASK;
+
+ read_buf[i] = data;
+ }
+
+ /* Restore registers */
+ __raw_writel(out_reg, base + AR71XX_GPIO_REG_OUT);
+ __raw_writel(oe_reg, base + AR71XX_GPIO_REG_OE);
+ /* Flush write */
+ __raw_readl(base + AR71XX_GPIO_REG_OUT);
+
+ rb91x_nand_latch_lock(drvdata, 0);
+
+ /* Disable read mode */
+ gpiod_set_value_cansleep(drvdata->gpio[RB91X_NAND_READ], 0);
+}
+
+static int rb91x_nand_dev_ready(struct nand_chip *chip)
+{
+ struct rb91x_nand_drvdata *drvdata = (struct rb91x_nand_drvdata *)(chip->priv);
+
+ return gpiod_get_value_cansleep(drvdata->gpio[RB91X_NAND_RDY]);
+}
+
+static void rb91x_nand_cmd_ctrl(struct nand_chip *chip, int cmd,
+ unsigned int ctrl)
+{
+ struct rb91x_nand_drvdata *drvdata = chip->priv;
+
+ if (ctrl & NAND_CTRL_CHANGE) {
+ gpiod_set_value_cansleep(drvdata->gpio[RB91X_NAND_CLE],
+ (ctrl & NAND_CLE) ? 1 : 0);
+ gpiod_set_value_cansleep(drvdata->gpio[RB91X_NAND_ALE],
+ (ctrl & NAND_ALE) ? 1 : 0);
+ gpiod_set_value_cansleep(drvdata->gpio[RB91X_NAND_NCE],
+ (ctrl & NAND_NCE) ? 1 : 0);
+ }
+
+ if (cmd != NAND_CMD_NONE) {
+ u8 t = cmd;
+
+ rb91x_nand_write(drvdata, &t, 1);
+ }
+}
+
+static u8 rb91x_nand_read_byte(struct nand_chip *chip)
+{
+ u8 data = 0xff;
+
+ rb91x_nand_read(chip->priv, &data, 1);
+
+ return data;
+}
+
+static void rb91x_nand_read_buf(struct nand_chip *chip, u8 *buf, int len)
+{
+ rb91x_nand_read(chip->priv, buf, len);
+}
+
+static void rb91x_nand_write_buf(struct nand_chip *chip, const u8 *buf, int len)
+{
+ rb91x_nand_write(chip->priv, buf, len);
+}
+
+static void rb91x_nand_release(struct rb91x_nand_drvdata *drvdata)
+{
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(5,8,0)
+ mtd_device_unregister(nand_to_mtd(&drvdata->chip));
+ nand_cleanup(&drvdata->chip);
+#else
+ nand_release(&drvdata->chip);
+#endif
+}
+
+static int rb91x_nand_probe(struct platform_device *pdev)
+{
+ struct rb91x_nand_drvdata *drvdata;
+ struct mtd_info *mtd;
+ int r;
+ struct device *dev = &pdev->dev;
+ struct gpio_descs *gpios;
+
+ drvdata = devm_kzalloc(dev, sizeof(*drvdata), GFP_KERNEL);
+ if (!drvdata)
+ return -ENOMEM;
+
+ platform_set_drvdata(pdev, drvdata);
+
+ gpios = gpiod_get_array(dev, NULL, GPIOD_OUT_LOW);
+ if (IS_ERR(gpios)) {
+ dev_err(dev, "failed to get gpios: %d\n", (int)gpios);
+ return -EINVAL;
+ }
+
+ if (gpios->ndescs != RB91X_NAND_GPIOS) {
+ dev_err(dev, "expected %d gpios\n", RB91X_NAND_GPIOS);
+ return -EINVAL;
+ }
+
+ drvdata->gpio = gpios->desc;
+
+ gpiod_direction_input(drvdata->gpio[RB91X_NAND_RDY]);
+
+ drvdata->ath79_gpio_base = ioremap(AR71XX_GPIO_BASE, AR71XX_GPIO_SIZE);
+
+ drvdata->dev = dev;
+
+ drvdata->chip.priv = drvdata;
+
+ drvdata->chip.legacy.cmd_ctrl = rb91x_nand_cmd_ctrl;
+ drvdata->chip.legacy.dev_ready = rb91x_nand_dev_ready;
+ drvdata->chip.legacy.read_byte = rb91x_nand_read_byte;
+ drvdata->chip.legacy.write_buf = rb91x_nand_write_buf;
+ drvdata->chip.legacy.read_buf = rb91x_nand_read_buf;
+
+ drvdata->chip.legacy.chip_delay = 25;
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(5,9,0)
+ drvdata->chip.ecc.engine_type = NAND_ECC_ENGINE_TYPE_SOFT;
+ drvdata->chip.ecc.algo = NAND_ECC_ALGO_HAMMING;
+#else
+ drvdata->chip.ecc.mode = NAND_ECC_SOFT;
+ drvdata->chip.ecc.algo = NAND_ECC_HAMMING;
+#endif
+ drvdata->chip.options = NAND_NO_SUBPAGE_WRITE;
+
+ r = nand_scan(&drvdata->chip, 1);
+ if (r) {
+ dev_err(dev, "nand_scan() failed: %d\n", r);
+ return r;
+ }
+
+ mtd = nand_to_mtd(&drvdata->chip);
+ mtd->dev.parent = dev;
+ mtd_set_of_node(mtd, dev->of_node);
+ mtd->owner = THIS_MODULE;
+ if (mtd->writesize == 512)
+ mtd_set_ooblayout(mtd, &rb91x_nand_ecclayout_ops);
+
+ r = mtd_device_register(mtd, NULL, 0);
+ if (r) {
+ dev_err(dev, "mtd_device_register() failed: %d\n",
+ r);
+ goto err_release_nand;
+ }
+
+ return 0;
+
+err_release_nand:
+ rb91x_nand_release(drvdata);
+ return r;
+}
+
+static int rb91x_nand_remove(struct platform_device *pdev)
+{
+ struct rb91x_nand_drvdata *drvdata = platform_get_drvdata(pdev);
+
+ rb91x_nand_release(drvdata);
+
+ return 0;
+}
+
+static const struct of_device_id rb91x_nand_match[] = {
+ { .compatible = "mikrotik,rb91x-nand" },
+ {},
+};
+
+MODULE_DEVICE_TABLE(of, rb91x_nand_match);
+
+static struct platform_driver rb91x_nand_driver = {
+ .probe = rb91x_nand_probe,
+ .remove = rb91x_nand_remove,
+ .driver = {
+ .name = "rb91x-nand",
+ .owner = THIS_MODULE,
+ .of_match_table = rb91x_nand_match,
+ },
+};
+
+module_platform_driver(rb91x_nand_driver);
+
+MODULE_DESCRIPTION("MikrotTik RB91x NAND flash driver");
+MODULE_VERSION(DRV_VERSION);
+MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
+MODULE_AUTHOR("Denis Kalashnikov <denis281089@gmail.com>");
+MODULE_LICENSE("GPL v2");
projects / openwrt / staging / dedeckeh.git / commitdiff